The Quad Cities area was known to river boat pilots as 13 miles of
dangerous rapids during high water, and 13 miles of impossible rapids
during low water. The US Army Corps of Engineers worked to clear the
snags and build wing dams, but that was more of a band aid than a
solution to the rapids.

The first attempt to solve the navigation problem involved building
a canal and lock around the worst of the rapids upstream near the
present day Lock & Dam #14. That was built for the 6-foot
navigation project. While a modern dam with 9-foot locks have been
built at that site, the canal and 6-foot lock is still in use for
pleasure craft.

After World War I, technology lead to larger river boats that required
a deeper draft. Congress funded the 9-foot navigation project. This
project required that the Le Claire lock and dam be upgraded from a
6-foot structure to a 9-foot structure. At the same time, a second
9-foot structure would be required only a few miles downstream. The
site that was picked was between Davenport and Rock Island, at the
foot of Arsenal Island. Construction was tricky because the double
deck Government rail and road bridge crossed the site. In fact, that
bridge had a swing section to allow river traffic to pass. That swing
section was located between the two locks, and would swing to be parallel
with the center wall between the locks. This allowed both locks to be
clear for traffic to enter and exit while the swing span was open.

The dam is built with 11 gates. The gates are hollow metal tubes that
can be lowered into the water to block the river flow. Each gate is
109 feet wide. This is reported to be the largest dam in the world
made exclusively from roller gates. These roller gates were new
technology in the late 1920s. In fact, the US Army stole the
technology from Germany after WWI. Most other locks and dams on the
great river use a combination of roller gates and Tainter gates.